This script was built to allow one to quickly extrapolate data and information about the SSL certificate used on a large list of websites.

Get-Certs.psm1

<# 
This script was built to allow one to quickly extrapolate data and information about the SSL certificate used on a large list of websites.
Here is a breakdown of the logic:
 1. Open SSL tunnel to a FQDN
 2. Import the cert as a x509Certificate2 powershell object
 3. Extract the subject and issuer info from the certificate
 4. Compiles a CSV report with the certificate details
#>
function Get-Certs
{
    Param
    (
         [Parameter(Mandatory=$true)]
         [ValidateScript({
            if (Test-Path $_){
                $true
            }
            else{
                throw "File $($_) does not exist."
            }
         })]
         [ValidateNotNullOrEmpty()]
         $in,
         [Parameter(Mandatory=$true)]
         [ValidateScript({
            if (Test-Path -IsValid $_){
                $true
            }
            else{
                throw "$($_) is not a valid filepath."
            }
         })]
         [ValidateNotNullOrEmpty()]
         $out
    )
    $out_csv = @()
    $in_csv = Import-Csv -Path $in| ForEach-Object{       
        foreach($property in $_.PsObject.Properties)
        {
            <#
            The domain is in $property.Value
            CSV header "FQDN" is in $property.Name
            #>
            $fqdn = $property.Value.ToString()
            [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12; # use TLSv1.2, powershell defaults to TLSv1
            $webRequest = [Net.WebRequest]::Create("https://$($fqdn)")
            try { $webRequest.GetResponse() } catch {}
            $fqdn = $webRequest.Address
            $cert = $webRequest.ServicePoint.Certificate
            $bytes = $cert.Export([Security.Cryptography.X509Certificates.X509ContentType]::Cert)
            $Cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2
            $Cert.Import($bytes)

            # Create CSV rows and append to out_csv
            $row = [pscustomobject]@{
                FQDN = $fqdn
                Subject  = ($Cert.Subject.ToString() -replace ',(?=(?:[^"]*"[^"]*")*[^"]*$)', ";").Replace(",", " ") # replace commas so they dont interfere with csv
                Issuer  = ($Cert.IssuerName.Name.ToString() -replace ',(?=(?:[^"]*"[^"]*")*[^"]*$)', ";").Replace(",", " ") # replace commas so they dont interfere with csv
                Serial_Number = $Cert.GetSerialNumberString()
            }
            $out_csv += $row
        }
    }
    # Save csv
    $out_csv | Export-Csv -Path $out -NoTypeInformation

}
Export-ModuleMember -Function Get-Certs

You can import the module in powershell with Import-Module Get-Certs.psm1

The in file should be a list of domains on new lines. For example:

domain.com
domain2.com
domain3.net